Totally normal. March of progress. Old stuff goes away.
If diskutil actually did everything OP looks for that was available in hdiutil, that's correct. If you read the post though, you'll see that diskutil has many limitations compared to its predecessor.
Progress is when we make things worse just because we can.
Username relevant as always.
diskutil is for disks (e.g., volumes) while hdiutil is for disk images ("file system as a file"). They're not two versions of the same thing, so it doesn't make sense to dub deprecating hdiutil as "progress."